It is difficult during joint replacement within the human body to maintain the exact overall leg dimension after surgery. This is especially true when large joints such as hips, are repaired and or completely replaced. A good description of the length problems associated with hip surgery is found in the September, 2001 Journal of Arthroplasty, Volume 16, entitled xe2x80x9cCorrection of Limb-Length Inequality During Total Hip Arthroplastyxe2x80x9d.
One method for comparing leg length before and after hip surgery is described within U.S. Pat. No. 6,027,507 entitled xe2x80x9cLeg Length Gauge for Total Hip Replacementxe2x80x9d, wherein a removable gauge having pin-receiving apertures is employed.
U.S. Pat. No. 5,606,590 entitled xe2x80x9cSurgical Laser Beam-based Alignment System and Methodxe2x80x9d describes a sophisticated x-ray console that includes a laser source and lens for providing alignment during orthopedic surgery.
A further use of a laser distance detector for manufacturing operations is found in U.S. Pat. No. 4,733,969 entitled xe2x80x9cLaser Probe for Determining Distance.xe2x80x9d
This arrangement employs lenses along with an electronic circuit, which functions as a coordinate measuring machine.
U.S. patent application Ser. No. 09/679,622 now U.S. Pat. No. 6,383,149 entitled xe2x80x9cLaser Length Discrepancy Devicexe2x80x9d describes a pair of laser diodes separated a fixed distance from each other within a hand-held console for determining the position of hip and leg after hip replacement surgery for allowing adjustment thereto. However, upon the occurrence of heavy bleeding or bruise formation, some additional time is required to clean up the leg portion for providing visual access to the reflection of the laser beam from the hip.
It would be economically advantageous to utilize the precision focus of an inexpensive laser diode in combination with an extended pin, after hip surgery without having to thoroughly clean the surface of the hip to determine the position thereof.
One purpose of the instant invention is to provide a simple, non-invasive arrangement of an extended pin and a laser diode for determining pre-operative and post-operative limb and joint distance for maintaining or correcting the distance after surgical joint replacement.
A hand-held measurement console in the form of an enclosure containing an extended pin and a laser diode is used in conjunction with a pair of temporary markers in the form of screws, indelible markings and the like, to determine a reference distance prior to joint replacement surgery. Immediately after surgery, the lasers are directed on the temporary markers to compare the post surgery distance to the reference distance and appropriate adjustments are made to cause the post-surgery distance to correspond to the pre-surgery reference distance or the desired leg length correction.